Effects of ruminal short-chain fatty acid concentration and pH on histology, hematology, and inflammation in cannulated Holstein dairy calves
Bibliographic record
Abstract
Optimizing rumen development is key to preparing calves for weaning; however, it is unclear what effect rumen development has on calf health via ruminal infusion. This study investigated the effects of ruminal short-chain fatty acid (SCFA) concentrations and pH on hematology, gut morphology, and inflammation of liver and rumen tissues in dairy calves. Holstein calves (n = 32) had the rumen cannulated within the first week of life and at wk 2 were blocked by BW and randomly assigned in a 2 × 2 factorial arrangement of treatments. The treatments included 2 different SCFA concentrations (10 vs. 285 mM) and pH levels (5.2 vs. 6.2), yielding 4 treatment groups: low SCFA, low pH (LS-LP); low SCFA, high pH (LS-HP); high SCFA, low pH (HS-LP); and high SCFA, high pH (HS-HP). On wk 3, 5, and 7, calves underwent a 4-h reticulorumen wash procedure with a physiological buffer containing the various treatments. Blood samples were collected weekly after feeding. Rumen biopsies were taken after each infusion, and liver and rumen samples were harvested at necropsy at wk 7. Data were analyzed with repeated measures, using week, SCFA, and pH as fixed effects. Low rumen pH increased respiration rate, but no other changes in clinical parameters were observed. No differences were detected in red blood cells or platelet numbers. Total white blood cell numbers decreased in the LS-LP group from wk 5 to 7 but increased in the HS-LP group along with hemoglobin and the hematocrit during the same period. Cortisol and BHB levels were unchanged by treatment or time, whereas haptoglobin decreased over time regardless of treatment. Calf liver morphology was unaffected by treatment; ruminal tissue changes associated with epithelial cell sloughing tended to increase with low SCFA, and mucosal eosinophil infiltration increased with high SCFA. Gene expression was unchanged by treatment in both rumen (barrier function and inflammation) and liver (inflammation). Overall, the data demonstrate that stress and inflammatory responses can be affected by changing rumen environments. Notably, these changes are transient as values returned to pretreatment baseline levels after a period as short as a week.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".